> -----Original Message----- > From: Bruce Richardson [mailto:bruce.richard...@intel.com] > Sent: Tuesday, September 10, 2019 2:20 PM > To: Zapolski, MarcinX A <marcinx.a.zapol...@intel.com> > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [RFC 19.11 v2 1/3] ethdev: hide key ethdev > structures from public API > > On Tue, Sep 10, 2019 at 11:13:50AM +0100, Zapolski, MarcinX A wrote: > > > -----Original Message----- > > > From: Bruce Richardson [mailto:bruce.richard...@intel.com] > > > Sent: Tuesday, September 10, 2019 12:07 PM > > > To: Zapolski, MarcinX A <marcinx.a.zapol...@intel.com> > > > Cc: dev@dpdk.org > > > Subject: Re: [dpdk-dev] [RFC 19.11 v2 1/3] ethdev: hide key ethdev > > > structures from public API > > > > > > On Tue, Sep 10, 2019 at 09:59:51AM +0000, Zapolski, MarcinX A wrote: > > > > <...> > > > > > @@ -3994,7 +4054,55 @@ void * > > > > > rte_eth_dev_get_sec_ctx(uint16_t port_id); > > > > > > > > > > > > > > > -#include <rte_ethdev_core.h> > > > > > +struct rte_eth_dev_callback; > > > > > +/** Structure to keep track of registered callbacks */ > > > > > +TAILQ_HEAD(rte_eth_dev_cb_list, rte_eth_dev_callback); > > > > > + > > > > > +/** > > > > > + * Structure used to hold information about the callbacks to be > > > > > +called for a > > > > > + * queue on RX and TX. > > > > > + */ > > > > > +struct rte_eth_rxtx_callback { > > > > > + struct rte_eth_rxtx_callback *next; > > > > > + union{ > > > > > + rte_rx_callback_fn rx; > > > > > + rte_tx_callback_fn tx; > > > > > + } fn; > > > > > + void *param; > > > > > +}; > > > > > + > > > > > +/** > > > > > + * The generic data structure associated with each ethernet device. > > > > > + * > > > > > + * Pointers to burst-oriented packet receive and transmit > > > > > +functions are > > > > > + * located at the beginning of the structure, along with the > > > > > +pointer to > > > > > + * where all the data elements for the particular device are > > > > > +stored in shared > > > > > + * memory. This split allows the function pointer and driver > > > > > +data to be per- > > > > > + * process, while the actual configuration data for the device is > shared. > > > > > + */ > > > > I would like to raise one more concern (maybe not the smartest > > > > thing to do involving my own patch, but I will sleep better when this is > resolved). > > > > Does anyone know what the author of this comment had in mind? I > > > > could not find any code that utilizes this split, and this patch > > > > clearly breaks it. If it is obsolete, I guess this comment could be > removed. > > > > > > As the comment suggest the split is for multi-process suport. The > > > data structures for the RX/TX queues etc. all need to be common > > > across processes, while the function pointers need to be > > > per-process. Originally, in very early versions of DPDK there was no > > > rte_eth_dev_data structure, all fields - both data and function pointers - > were in rte_eth_dev itself. > > > > > > /Bruce > > > > Yes, I see the need to have the elements separated. But the comment > > suggests that the order of variables in structure is important. I just > > want to make sure that it is not. > > I don't believe it's particularly significant. The main thing was to ensure > that > we kept the fast-path accessed data on the same cacheline.
Thank you for clarifying.
